I need to install three input switches corresponding to which there are three LEDs that show the status of the switches.
I was certain to use macanical switches. But just got to know a bit more about the CAP SENSE capability of PSoc chips.
So m thinking to give a try to the CAPSENSE version.
There's a PCB containing three LEDs
Above the LED is 1mm thick diffusing epoxy
Above the epoxy is 1mm transparent glass. The user will touch this glass.
I want to make the capsense pads just below the LED. Size of pad is approx 4mmx2mm
A 3D photo is attached for better understanding.
Am I thinking in the correct direction or am I incorrect in the approch?
I have zero experience with cap sense.
Very helpful indeed! Thanks...
If we use capsense, then can we use the IDAC for analogue purpose, or will it be 'taken over' by the capsense block?
There are four IDACs within a PSoC4: two 8-Bit and two 7-bit ones. You may use two of those for your own program (one 7-bitand one 8-bit) and the other you may use for capsense. When in need of another 7-bit IDAC then you may use that with a little bit restricted configurations of the CapSense. See CapSense datasheet, chapter "CapSense Analog System" on pg. 74.
4 IDACs or 2 IDACs ? From the TRM -
23.6 General-Purpose Resources
If the CapSense block is not used for touch sensing, the two
IDACs can be used as general-purpose analog blocks.
The 8-bit IDAC can operate in either 0 to 306 µA (1.2 µA/bit)
or 0 to 612 µA (2.4 µA/bit) ranges. The 7-bit IDAC supports
0 to 152.4 µA (1.2 µA/bit) and 0 to 304.8 µA (2.4 µA/bit)
Both the 8-bit and 7-bit IDACs can connect to GPIOs using
AMUXBUS A and AMUXBUS B. It is also possible to con
nect both IDACs to a single AMUXBUS. The IDACS can
operate in three different modes: CSD-only mode, General
purpose (GP) mode, and CSD and GP mode. Table 23-1
describes how IDAC1 and IDAC2 are connected to AMUX
BUS A and AMUXBUS B in each of these modes.
From 42xx resources page -
8-bit CapSense IDACs : 1 : 0 : 1 : 100.00%
7-bit CapSense IDACs : 1 : 0 : 1 : 100.00%